Induced sludge bed anaerobic reactor system

ABSTRACT

An induced sludge bed anaerobic reactor system that includes at least two stages of bioreactor processing, a first-stage feeding system, a second-stage feeding system, a pH balancing system, an effluent recirculation system, a gas management system, at least one nitrogen reduction system, and a controller. In addition, the nitrogen reduction system(s) if configured for reducing an amount of one or more nitrogen compounds in a substrate mixture sufficient to procedure a non-toxic substrate mixture with respect to anaerobic digestion of the non-toxic substrate by the induced sludge bed anaerobic reactor system.

RELATED APPLICATION(S)

This application is a Continuation in Part and claims benefit from orpriority of U.S. patent application Ser. No. 16/746,848 that was filedJan. 18, 2020, which is a Continuation of and claims benefit from orpriority of U.S. patent application Ser. No. 16/058,850 (U.S. Pat. No.10,570,043) that was filed Aug. 8, 2018 (issued Feb. 25, 2020), which isa Continuation in Part of U.S. patent application Ser. No. 15/253,727(U.S. Pat. No. 10,071,925), filed Aug. 31, 2016 (issued Sep. 11, 2018),each of which is incorporated herein by reference in its entirety.

SUMMARY

The summary provided in this section summarizes one or more partial orcomplete example embodiments of the technologies described herein inorder to provide a basic high-level understanding to the reader. Thissummary is not an extensive description of the technologies, is notlimiting, and it may not identify key elements or aspects of thetechnologies, or delineate the scope of the technologies. Its solepurpose is to present various aspects of the technologies in asimplified form as a prelude to the detailed description provided below.The technologies as a whole shall not be limited to any particularembodiment(s) or example(s) or combination(s) therefore provided herein.

This invention relates to anaerobic digestion of substrate inwastewater. More particularly, this invention relates to processes anddevices to enhance and improve the anaerobic digestion process, tominimize bacteria loss and reactor plugging, to protect against biogasoverpressure, and to reduce mechanical complexity and maintenance needs.In general, this invention comprises an induced sludge bed anaerobicreactor system that typically includes at least two stages of bioreactorprocessing, a first-stage feeding system, a second-stage feeding system,a pH balancing system, an effluent recirculation system, a gasmanagement system, at least one nitrogen reduction system, and acontroller. In addition, any given stage of bioreactor processing may becomprised of a plurality of reactors that are configured to operate inparallel with each other.

The foregoing and other features, utilities, and advantages of theinvention will be apparent from the following detailed description ofthe invention with reference to the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

The detailed description provided below will be better understood whenconsidered in connection with the accompanying drawings, where:

FIG. 1 is a perspective view of an example bioreactor according to thepresent invention.

FIG. 2 is a front elevation view, including a sectional view showinginterior portions, of the example bioreactor.

FIG. 3 is a representation of a waste particle, a bacterium, a gasbubble, and the interaction of these with a septum of the presentinvention.

FIG. 4 illustrates a length-wise sectional view of an example pair ofadjacent vanes of an example septum.

FIG. 5 illustrates a schematic diagram of examples including bioreactorand substrate tank.

FIG. 6 illustrates an example septum based on a linear vane design.

FIG. 7 illustrates an example septum based on a concentric vane design.

FIG. 8 illustrates an example septum based on a radial vane design.

FIG. 9 illustrates an example attachment scheme for attaching a septumto the inside of a vessel.

FIG. 10 is a schematic diagram that illustrates an example of inducedsludge bed anaerobic bioreactor system 1000 with, inter alia, two-stagesof reactor-based processing.

FIG. 11 is a schematic diagram that highlights components of thefirst-stage feeder system 1100 illustrated in FIG. 10.

FIG. 12 is a schematic diagram that highlights components of thefirst-stage reactor processing system 1200 illustrated in FIG. 10.

FIG. 13 is a schematic diagram that highlights components of thesecond-stage feeding system 1300 illustrated in FIG. 10.

FIG. 14 is a schematic diagram that highlights components of thesecond-stage reactor processing system 1400 illustrated in FIG. 10.

FIG. 15 is a schematic diagram that highlights components of pHbalancing system 1500 illustrated in FIG. 10.

FIG. 16 is a schematic diagram that highlights components of effluentrecirculation system 1600 illustrated in FIG. 10.

FIG. 17 is a schematic diagram that highlights components of gasmanagement system 1700 illustrated in FIG. 10.

FIG. 18 is a block diagram showing an example computing environment 100in which controller 1070 may be implemented.

FIG. 19 is a schematic diagram that illustrates example nitrogenreduction system 1900.

FIG. 20 is a schematic diagram that illustrates example nitrogenreduction system 2000.

FIG. 21 is a schematic diagram that illustrates example nitrogenreduction system 2100.

FIG. 22 is a diagram illustrating example method 2200 for reducing anamount of at least one nitrogen compound in a substrate or substratemixture resulting in a non-toxic substrate mixture for purposes ofanaerobic digestion by system 1000.

Like-numbered labels in different figures are typically used todesignate similar or identical elements or steps in the accompanyingdrawings.

DETAILED DESCRIPTION

The detailed description provided in this section, in connection withthe accompanying drawings, describes one or more partial or completeexample embodiments of the technologies, but is not intended to describeall possible embodiments of the technologies. This detailed descriptionsets forth various examples of at least some of the systems and/ormethods of the technologies. However, the same or equivalenttechnologies, systems, and/or methods may be realized according toexamples as well.

The present invention relates to an anaerobic reactor 10 comprising anenclosure or vessel in which wastewater containing high concentrationsof organic matter is introduced for treatment. An anaerobic reactor 10according to the present invention is particularly applicable towastewater generated through agricultural production and foodprocessing.

In the anaerobic digestion process, bacteria convert carbon-containingwaste products, such as byproducts of farming, ranching, or foodprocessing, into primarily biogas that is similar to natural gas.Suspended growth anaerobic digesters, such as lagoons or enclosedvessels, that are mixed and heated do not retain bacteria. Therefore,the rate of treatment depends on how fast the bacteria can grow. Forsimplicity, the term “bacteria” as used herein includes acidogens(producers of volatile organic acids), methanogens (producers ofmethane), and other microorganisms that may not technically beclassified as bacteria, such as archaeon-methanogens that are generallyconsidered to be a primitive form of bacteria, but that may contributeto the anaerobic digestion processes along with true bacteria.

An induced bed bioreactor (“IBR”) quickly forms a sludge bed within thebioreactor. A sludge bed refers to a region within a bioreactor that isthick with solids and a high concentration of living bacteria feeding onthe solids. The sludge bed initially consists of various types of solidparticles naturally found in biowaste, such as undigested feed or piecesof bedding. A sludge bed of this type is a haven for bacteria. Thebacteria will attach to the particles of waste in the wastewater.

If the sludge bed is controlled properly, the bacteria will grow withoutbeing flushed out of the bioreactor. If the sludge bed is managedproperly, it will evolve to comprise mostly living bacteria and thesolids upon which the bacteria feed. When the sludge bed is trapped in azone, the living bacteria multiply by consuming the solid, non-livingmaterial suspended in the bed and that flows up into the bed fromfeeding the bioreactor. Without some type of sludge bed controlmechanism, however, the wastewater passing through a continuously fedbioreactor would transport bacteria out of the bioreactor with theeffluent. This is not desirable because a high concentration of bacteriais necessary to effectively convert organic matter in the wastewater tobiogas.

Prior bioreactors have been developed to provide a high concentration ofbacteria to enhance the anaerobic digestion process. These priorbioreactors have added a fixed media, such as plastic rings or rocks, sothat the bacteria have something to which they can attach. A drawback ofthese prior bioreactors, however, is that they soon plug when processingsubstrates, the food for the microorganisms, such as animal manure andmany kinds of food processing wastes. They also employ no mechanism tocontrol formation of the sludge bed.

FIGS. 1-2 illustrate various views of example bioreactor 10 thatcomprises a vessel or tank 12, which typically comprises a cylindricalupstanding tank. The vessel 12 may be made of any suitable material,including but not limited to steel, plastic, or concrete. The vessel 12provides an enclosure into which wastewater 14 is fed. In one example,the vessel 12 is round in cross section and two to five times tallerthan its diameter. Other examples may take on other shapes and/orproportions. The wastewater to be processed or treated in vessel 12 maycomprise any type of biological waste products (also known as“substrate”), such as byproducts of farming, ranching, agriculture, foodprocessing, or any other type of wastewater that contains highconcentrations of organic matter. Wastewater 14 is typically introduced(fed into) at or near the bottom of vessel 12 through a substrate inlet16. The introduction of wastewater containing substrates is typicallyknown as ‘feeding’—that is, the wastewater is fed into the bioreactor.The wastewater may also include other waste materials, such as woodchips, bedding material, straw, baling twine, rocks, dirt, and othermaterials commonly found in animal manure, agricultural byproducts, andfood waste. The term “wastewater” as used herein is typically synonymouswith the term “substrate mixture” as used herein.

FIG. 2 illustrates aspects of an example partition or septum 20 that ispositioned inside vessel 12. In one example, septum 20 is disposedbetween approximately two-thirds and nine-tenths of the way up in vessel12. The septum may be rigid or semi-rigid, and may be comprised of anysuitable material, such as plastic, metal, or the like. It is also to beunderstood that the septum 20 may comprise a plurality of panels orparts, or may comprise a single, unitary piece of material. In anotherexample, a plurality of septums 20 of similar or different designs maybe layered one atop another. The space between layered septums may varyfrom two septums being stacked one immediately atop another to havingany desired spacing between one septum and another, and any combinationof the foregoing. In general, the objective of layering septums ofsimilar and/or different types as described here is to maximize thedegree to which bacteria are prevented from exiting the vessel 12 whileat the same time minimizing clogging.

Septum 20 may also help form and maintain the sludge bed below septum 20to retain anaerobic bacteria within the bioreactor. By retaining theanaerobic bacteria within the sludge bed area or zone, there remain morebacteria for breaking down the organics in the wastewater fed into thebioreactor. By utilizing an effective septum, such as septum 20,wastewater can be treated much faster and much more efficiently in theapparatus described in connection with the present invention as comparedto other prior bioreactors. This increases efficiency of operations andreduces capital costs, required maintenance and management, and makes iteasier to build and scale. The present invention also makes it mucheasier for an inexperienced operator to manage the anaerobic digesterwithout having to know how the anaerobic digester actually works.

With reference again to FIG. 1, several different ports may be providedin bioreactor 10. When sludge builds up toward the bottom of thebioreactor, a port 42, which may be of any suitable size, is providedfor cleaning out unwanted, sludge mixed with grit or sand or the like. Atop access port 44, which may be of any suitable size, may be providedat the top of vessel 12 for added accessibility to the top of theenclosure 12. A vent or gas outlet 46 formed at the top of vessel 12 maybe utilized to remove biogas generated within bioreactor 10. A loweraccess port 48 (closed during normal operation), which can be of anysuitable size, may be provided toward the lower end of the vessel 12 foraccess to the lower portion of vessel 12. A recirculation port 50 may beprovided to redirect sludge and/or wastewater above septum 20 to thelower portion of vessel 12, either through substrate inlet 16 or throughany other return line or port (not shown). Test ports 52, 54 may beprovided to test the wastewater or sludge bed at any number of locationsrelative to the vertical orientation of the tank. An effluent outlet 56may be provided to remove water that has passed through the continuouslyfed bioreactor. Preferably, water passing through effluent outlet 56will be treated wastewater that contains little bacteria. Cap 40 may notbe significant to or required in the examples described herein. Thoseskilled in the art will understand that any number of other outlets orports may be utilized in connection with the present invention withoutdeparting from the scope or spirit thereof.

Research suggests that the design of an effective septum depends on anunderstanding of the anaerobic digestion process and the bacteriainvolved in that process. The anaerobic digestion process is complex,involving various types of bacteria that work symbiotically, eachplaying a role in the breakdown of organics and the generation ofmethane and/or hydrogen. Anaerobic digestion can roughly be broken downinto three stages: (1) hydrolysis, (2) acidogenesis, and (3)methanogenesis. Specific types of bacteria are typically required foreach stage of the process, and are known to those skilled in the art. Inone example of a properly operating anaerobic digester, hydrolyzingbacteria break down larger substrate molecules which are then furtherbroken down by acidogens into volatile organic acids (VOAs). The VOAsare then consumed by the methanogens, which are known to produce methaneas a byproduct.

Acidogens tend to be faster growing than other types of anaerobicbacteria in most situations. This means that most anaerobic digestersmust be relatively lightly loaded with substrate to prevent acidogensfrom outgrowing the methanogens and thus producing more VOA than themethanogens can consume. If they do not, the pH (“potential ofhydrogen”) will drop into the acidic range, which inhibits methanogensand builds up acid in a downward spiral until no acids are removed andthe digester fails. This means that a limited amount of substrate (i.e.,organic matter in wastewater) can be added to most anaerobic digestersin any given time period so that processes of hydrolysis and acidproduction do not outstrip the ability of methanogens to utilize the VOAand thus the pH will be maintained near the neutral range and the systemis kept in balance.

As schematically represented in FIG. 3, a bacterium 520 will typicallyattach to a particle of waste 530 in wastewater 14 within an anaerobicdigester. Such waste particles 530 are generally referred to herein as“substrate” that are broken down or digested by bacteria. As gas bubble510 is produced by bacterium 520 the gas bubble tends to remain attachedto the bacterium causing it and any waste particle 530 to which it isattached to rise 550 upward at some point in the gas bubble's growth. Ifnothing stops this upward movement, bacterium 520 may reach the top ofwastewater 14 and exit vessel 12 with the effluent. Further, bacteriatend to clump together such that bacteria in a clump rise 550 together.Note that 520 may also represent a clump of bacteria, 530 multiple foodparticles (substrate), and 510 multiple or joined gas bubbles. Note thatnot all types of bacteria in an anaerobic reactor necessarily producegas bubbles, but it is known that methanogens tend to produce methanegas bubbles.

An effective septum design will prevent or minimize rising bacteria fromexiting the vessel. For example, rising bacterium/clump of bacteria 520will bump into the septum causing any bubbles 510 to dislodge andcontinue upward while causing the bacteria 520 and any attached wasteparticles 530 to fall back into the sludge bed. On the other hand, aless-effective septum design will allow rising bacterium/clump ofbacteria to exit vessel 12. For example, at least the aperture of theseptum design disclosed in U.S. Pat. No. 7,452,467, may allowundesirable quantities of bacteria to exist vessel 12.

In one more effective design example, septum 20 includes example vanes540 (not to scale) that serve to impede the upward movement of risingbacteria. As a result, rising bacterium 520 typically bump into one ofthe vanes such that bubble(s) 510 dislodges, allowing bacterium 520 andany attached waste particle 530 to fall back into the sludge bed, andalso allowing bubble(s) 510 to pass through septum 20 and out of vessel12 through gas outlet 46 or the like. In one example, vanes 540 ofseptum 20 are sized and positioned relative to each other so as tomaximize the probability that rising bacteria 520 will bump into a vanethus dislodging any bubbles 510, causing the bubble-less bacteria 520 tofall back into the sludge bed before they can exit bioreactor 10.

Some types of waste fed into bioreactor 10 may also float to the top ofvessel 12, including wood chips, bedding material, straw and balingtwine; materials commonly found in animal manure, agriculturalbyproducts, and food production waste. Rocks, dirt and sand tend tosink. In addition to or instead of floating, such waste may be moved tothe top of vessel 12 due to wastewater turbulence and the like in vessel12. Such waste is referred to herein as “clogging waste” that bacteriahas not yet broken down or that may not be able to break down. Suchclogging waste may come in all shapes and sizes, some of which may floator rise in wastewater 14 and contribute to clogging of bioreactor 10.Given such clogging waste, vanes 540 of septum 20 are sized and orientedrelative to each other so as to minimize the probability that floatingwaste will clog bioreactor 10, as described in more detail in connectionwith FIG. 4. The terms “clog” and “plug” and the like as used hereinrefer to a buildup(s) of clogging waste that result in a substantialreduction of the flow of the biogas produced within vessel 12. Thisbuildup may occur in one or more ports of the bioreactor, in the septumitself, and/or in any other part(s) of the bioreactor that can result inclogging. The terms “clogging” and “plugging” and the like as usedherein refer to the forming of a clog or plug within vessel 12. Forexample, real-world usage of the septum design disclosed in U.S. Pat.No. 7,452,467 reveals that the aperture of the septum may be clogged bywaste, even when using the auger and mixer components disclosed.

FIG. 4 illustrates a length-wise sectional view of an example pair ofadjacent vanes 540 of an example septum and further illustratescharacteristics of the pair that are generally shared by essentially allpairs of adjacent vanes of a more effective septum design. Inparticular, dimension w indicates the width of the vanes, angle aindicates the angle of the vanes relative to horizontal plane 610,dimension p indicates the parallel distance between the vanes, dimensiono indicates the overlap distance of the vanes relative to horizontalplane 610, and distance h indicates the vertical height of the vanesrelative to horizontal plane 610.

An effective septum will minimize bacteria loss—the amounts of bacteriathat exit bioreactor 10 during operation- and will also minimizeclogging of bioreactor 10. In general, as bacteria loss and cloggingapproach zero, the more effective septum 20 is. This effectiveness istypically a function of characteristics of adjacent pairs of theseptum's vanes in terms of w, p, o, a, and h. In one example, for aneffective septum design, each vane is substantially w in width and isoriented at angle a relative to imaginary horizontal plane 610 of septum20 on which a lower edge of each vane is situated. Any two adjacentvanes are physically oriented relative to each other such that vanewidth w, angle a, and parallel distance p provide a minimum overlapdistance o. Parallel distance p is typically selected to be greater thanthe maximum rigid dimension of clogging waste anticipated to enterbioreactor 10. Further, vane width w, angle a, and parallel distance pare typically selected to provide at least a minimum overlap distance othat is greater than zero. In one example, dimension w is one to threetimes the parallel distance p, angle a is 45 degrees or less, and theoverlap distance o is zero and three-fourths the width w. The term“maximum rigid dimension of clogging waste” typically refers across-sectional dimension of clogging waste that is sufficiently largeand rigid to cause the waste to lodge between vanes or the like of aseptum. For example, consider a clogging waste cross-section with amaximum rigid dimension that is greater than p, such a maximum rigiddimension is considered sufficient to cause the waste to lodge betweenvanes or the like of a septum. Alternatively, consider a clogging wastecross-section with a maximum dimension that is greater than p but thatis not sufficiently rigid. Such clogging waste may deform along thedimension due to its lack of rigidity such that it will not lodgebetween vanes or the like of a septum. Thus, the term refers to bothsufficient dimension and rigidity for lodging between vanes or the likeof a septum.

In another example, the minimum overlap distance o is selected to besufficient to maximize the probability that rising bacteria that reachthe septum will bump into a vane as opposed to passing through theseptum un-obstructed, thus causing any bubbles to dislodge and thebacteria to fall back into the sludge bed as opposed to exitingbioreactor 10 in the effluent. Note that the rise of floating bacteriamay not be 100% vertical; turbulence and currents and the like in thewastewater may cause at least horizontal movement of rising bacteria.Thus, in one example, the minimum overlap distance o is selected to begreater than the anticipated horizontal movement of rising bacteria overdistance h.

Given that parallel distance p has a significant influence on vane widthw and overlap distance o, and given that parallel distance p isgenerally selected to be greater than the maximum rigid dimension ofclogging waste anticipated to enter bioreactor 10, in one example amacerator 710 is coupled to inlet 16 through which the substrate 722enters bioreactor 10. Macerators, as known by those skilled in the art,are used to break up solids and the like, such as substrate 722, so asto substantially ensure the maximum size of any solids or the likepassing through the macerator. Thus, a macerator(s) can be used to limitthe maximum rigid dimension of substrate (including clogging waste) thatenters bioreactor 10 to a particular maximum size.

Note that in certain configurations the vane width is may vary along thelength of the vanes, such as in the radial vane configuration detailedbelow. In other septum configurations, such as the linear and concentricvane configurations detailed below, the vane width w may remainsubstantially constant over the length of the vanes.

In some examples, septum 20 may be conical in shape; that is, raisedfrom the side walls of the vessel 12 to septum apex 80. For example, theelevation between the periphery of septum 20 and septum apex 80 may beapproximately ten to twenty inches. However, according to otherexamples, the elevation between the periphery of septum 20 at the wallsof the vessel 12 and a septum apex may be relatively shallow. Forexample, according to some embodiments, the elevation between theperiphery of septum 20 and the apex may be approximately one to threeinches. A more flat or shallow septum 20 may facilitate higher bacteriaconcentrations in the vessel 12 by holding more of the bacteria in thelower portion 750 of vessel 12.

FIG. 5 illustrates a schematic diagram of examples including bioreactor10 and substrate tank 720 comprising substrate 722 that is fed intovessel 12 via substrate inlet 16 through a macerator 710 which breaks upthe substrate so as to limit the maximum rigid dimension of substrate722 (including any clogging waste in the substrate) that entersbioreactor 10 to a particular maximum size. Further illustrated is arepresentation of a sludge bed 730 induced in a lower portion 750 ofvessel 12 and suspended in wastewater 14. The lower portion 750 ofvessel 12 is located in an area of vessel 12 below effluent outlet 56and septum 20 and further located in the area of vessel 12 abovesubstrate inlet 16. Arrow 740 indicates an overall up-flow generated inwastewater 14 from substrate 722 entering vessel 12 through inlet 16,effluent exiting vessel 12 via effluent outlet 56 and biogas 12 risingin wastewater 14 and exiting vessel 12 via biogas outlet 46. Septum 20is typically situated within wastewater 14 above inlet 16 and sludge bed730 (i.e., above lower portion 750) and below effluent outlet 56. In oneexample, septum 20 operates to retain sludge bed 730 in lower portion750 while minimizing bacteria loss from and clogging of bioreactor 10.In other examples, multiple septums (typically oriented one aboveanother) are so used.

FIG. 6 illustrates an example septum 600 based on a linear vane design,which is a specific type of example septum 20. An examplethree-dimensional view 600 of a linear-vane septum is illustrated. Inthis example design, the vanes are substantially straight and areoriented so as to be substantially parallel to each other, as can beseen in the top and sectional views of illustration 601. In particularwith this linear vane design, the characteristics of the adjacent pairsof vanes 540 are maintained consistent with those described inconnection with FIG. 4. Further, the septum ends 602 are typicallyplugged or otherwise structured so as to not allow rising bacteria topass through the septum 700 unobstructed consistent with theconsiderations discussed with respect to FIG. 4.

FIG. 7 illustrates an example septum 700 based on a concentric vanedesign, which is a specific type of example septum 20. An examplethree-dimensional view 700 of a concentric-vane septum is illustrated.In this example design, the vanes are oriented in concentric circles, ascan be seen in the top and sectional views of illustration 701. Inparticular with this concentric vane design, the characteristics of theadjacent pairs of vanes 540 are maintained consistent with thosedescribed in connection with FIG. 4. Further, the septum center region702 is typically plugged or otherwise structured so as to not allowrising bacteria to pass through the septum 700 unobstructed consistentwith the considerations discussed with respect to FIG. 4.

FIG. 8 illustrates an example septum 800 based on a radial vane design,which is a specific type of example septum 20. An examplethree-dimensional view 800 of a radial-vane septum is illustrated. Inthis example design, the vanes are oriented so as to extend out radiallyfrom the center region of each section to an outside edge of thesection, as can be seen in the top and sectional views of illustration801. In particular, with this radial vane design, the characteristics ofthe adjacent pairs of vanes 540 are maintained consistent with thosedescribed in connection with FIG. 4. Further, the septum center region802 is typically plugged or otherwise structured so as to not allowrising bacteria to pass through the septum 800 unobstructed consistentwith the considerations detailed with respect to FIG. 4.

In addition, a radial-vane septum 800 may include one or more sections,such as example sections 803 and 804 illustrated in FIG. 8. The numberof sections in the radial vane design typically depends on the length ofthe vanes with respect to a maximum desired septum height h. Note thatin the radial vane design the vanes are not actually parallel. Instead,the distance p increases between the vanes over their length from asection center region to a section outside edge. As the vanes becomelonger their widths w and/or angles a typically need to increase/changeso as to maintain the minimum overlap distance o of the characteristicsof adjacent pairs of vanes 540 described in connection with FIG. 4. Asthe length of the vanes increase, the vane width w may becomesufficiently large so as to increase the height h of the septum 800greater than is desirable. To avoid this problem, any number ofadditional sections can be implemented in a single septum. In general,the number of sections implemented would be at least the number requiredto not exceed a desired septum height h while still maintaining theadjacent vane characteristics described in connection with FIG. 4.

FIG. 9 illustrates an example attachment scheme for attaching a septum20 to the inside of a vessel. In general, one or more attachment device910 is used to attach septum 20 to the inside of vessel 12. Side 21 ofseptum 20 indicates its attachment side. Side 22 of septum 20 indicatesits free side. In one example, the center region of the point(s) ofattachment on attachment side 21 of septum 20 to the inside of vessel 12is typically substantially opposite effluent outlet 56.

Attachment device(s) 910 may be fabricated from wire, chain, plastic, orany other material that meets the following requirements. Attachmentdevice(s) 910 are sufficiently flexible to allow septum 20 to move andpitch within or upon wastewater 14 in any turbulence or the like suchthat the movement of free side 22 may allow any clogging waste floatingunder septum 20 to exit effluent outlet 56. Further, attachmentdevice(s) 910 are sufficient in number, location, and design so as toprevent septum 20 from flipping over or otherwise failing in its purposeto prevent or minimize rising bacteria from exiting the vessel 12.Further, attachment device(s) 910 are also sufficiently robust so as toprovide long-term mechanical reliability without breakage or failure ofthe device(s) 910. For example, attachment device(s) 910 may befabricated from stainless steel chain or the like and permanently orirremovably attached to vessel 12 and septum 20 via any suitable means.

FIG. 9 also illustrates an example optional jet 920 such as a water jetoriented so as to flush any clogging waste from septum 20. Typically,such water jets are optionally oriented around the inside wall and/or atvarious locations at the top of vessel 12 with their high-pressureoutlet nozzles aimed at various portions (e.g., top and/or bottom) ofseptum 20 or any number of septums within vessel 12 so as to sprayacross and/or into and/or through the vanes of the septum(s). The jetsmay be controlled separately and/or in groups and/or all together so asto flush any clogging waste from septum 20, thus cleaning septum 20 ofany built-up clogging waste or any other debris or the like. Varioussuch jets may be mounted inside vessel 12 and/or pass through the outersurface of vessel 12. In one example, such jets are connected to aninlet pipe(s) that provides water or the like to the inlet side of thejets. In another example, one or more such jets is aimed at a site glassmounted in the side of vessel 12 so as to clear the glass of any visualobstructions or the like. The water or the like fed to the jet inletsmay be potable water from an external source and/or may be liquid takenfrom inside vessel 12, and is typically cleaned (e.g., filtered or thelike) sufficiently so as to not clog the jets. In addition to flushingclogging waste or the like from a septum(s), the jet(s) may also beoriented so as to move such waste toward effluent outlet 56.

FIG. 10 is a schematic diagram that illustrates an example of inducedsludge bed anaerobic bioreactor system 1000 with, inter al/a, two-stagesof reactor-based processing. The terms “reactor,” “bioreactor,” and“anaerobic bioreactor” as used here refer to the same things unlessotherwise indicated. The first stage of reactor processing 1200 istypically performed by anaerobic bioreactor 10 ₁ and the second stage ofreactor processing 1400 is typically performed by anaerobic bioreactor10 ₂. In addition to these two stages of reactor processing, system 1000also includes several other subsystems: first-stage feeding system 1100,second-stage feeding system 1300, pH balancing system 1500, effluentrecirculation system 1600, gas management system 1700, and controller1070, each subsystem comprising one or more of the componentsillustrated in FIG. 10.

The term “conduit” as used herein refers to any suitable pipe, tube,hose, channel, or other passageway through which solids, liquids,gasses, and/or mixtures of the foregoing (“materials”) may be drawn,pumped, or otherwise moved. Different conduits in system 1000 may beused to move various materials, such as, for example, substrates,solids, water in its various forms, other liquids, effluents, gases,combinations of the foregoing, and the like. Such materials may havevarious characteristics such as temperature, acidity, corrosiveness,abrasiveness, viscosity, and the like and/or may be under some amount ofpressure or vacuum. Such characteristics may vary over time. Further,system 1000, or portions thereof including its conduits, may be subjectto various environmental conditions including vibrations, temperatureand/or pressure variations and extremes, acidic and/or alkalinesubstances and/or conditions, and the like. As such, each of theconduits in system 1000 may include various combinations of properties,characteristics, or capabilities sufficient to perform its intendedfunction under the environmental conditions and subject to thecharacteristics of the materials that move through it.

The term “control valve” as used herein refers to a valve used tocontrol the flow of one or more kinds of materials, as defined above, byopening or closing a flow passage as directed by a signal from acontroller, such as controller 1070. In other examples, a more advancedcontrol valve controls material flow by varying the size of the flowpassage in order to realize a particular rate of flow through the valve.In other examples, a control valve may include an integrated pumpingmechanism, or operate in conjunction with a separate pumping mechanism,to insure the controller-specified flow or flow rate through the valve.

The terms “heater” and “heating device” as used herein refer to any kindof heating mechanism, including those that operate on gas, electricity,solar, or otherwise, that can bring one or more kinds of materials, asdefined above, up to a temperature as directed by a controller, such ascontroller 1070. The terms “reducer” and “cooling device” as used hereinrefer to any kind of cooling mechanism, including a heat exchanger,radiator, cooling device, or other mechanism, that can bring one or morekinds of materials, as defined above, down to a temperature as directedby a controller, such as controller 1070. Further, such a heater mayinclude an integrated reducer, or operate in conjunction with a separatereducer, so as to bring the temperature of materials up or down asdirected by a controller. Further, such a reducer may include anintegrated heater, or operate in conjunction with a separate heater, soas to bring the temperature of materials up or down as required by acontroller.

First-stage feeding system 1100. In general, under the control ofcontroller 1070, this system performs the function of preparingsubstrate and feeding it into the first stage of reactor processing1200. Substrate preparation typically includes receiving raw substratein container 1020, optionally macerating the raw substrate, mixing themacerated substrate with water or effluent, and optionally adjusting thetemperature of the mixed substrate to be substantially the same as thefirst-stage processing temperature. The prepared substrate is thenpumped or otherwise fed into first-stage reactor 10 ₁ for processing.

FIG. 11 is a schematic diagram that highlights components of thefirst-stage feeder system 1100 illustrated in FIG. 10. In some examples,this system comprises substrate container 1020 that is configured tohold raw substrate 722, sensor 1001, conduit 1071, macerator 1022,conduit 1072, mixer 1026, control valve 1043, conduit 1080, controlvalve 1040, conduit 1073, pump 1028, conduit 1074, heater 1010 f, andconduit 1074 b. The phrase “raw substrate” as used herein refers tosubstrate as it is provided to system 1000 when placed or collected incontainer 1020 where the substrate has not yet been processed by system1000. In brief, first-stage feeder system 1100 is typically configuredto optionally macerate raw substrate, to mix substrate, including themacerated substrate, with water and/or second-stage effluent resultingin a substrate mixture, to optionally bring the temperature of thesubstrate mixture to be substantially the same as that of the wastewaterused in the first-stage of reactor processing, and to pump or feedsubstrate mixture into the first-stage of reactor processing. The term“mixer” as used herein, such as for mixer 1026, typically refers to anapparatus that is distinct from and different than a “vessel” as thatterm is used herein, such as reactor vessels 12 and pre-processingvessels such as vessel 12 _(p) (illustrated in FIG. 21).

In some examples, first-stage feeding system 1100 includes at least onesubstrate container 1020 which may be any combination of one or moretanks, hoppers, vessels, reservoirs, or the like (typically depending onthe substrate or substrates that system 1000 is designed to process)that receive and hold one or more similar or different substrates fromoutside of system 1000. Each container 1020 includes one or more sensors1001 of different or similar types that enable controller 1070 to detectthe presence, level, amount, weight, mass, and/or type of substrate 722,and/or various characteristics thereof.

In some examples, raw substrate 722 is fed or drawn intermittently orcontinuously from container 1020 through conduit 1071 into macerator1022, which performs essentially the same function as macerator 710described above. Macerator 1022 is typically operated by controller1070. In some embodiments, macerator 1022 may perform a pumping functionas well, typically under the control of controller 1070. In brief,macerator 1022 is configured to limit a maximum rigid dimension of thesubstrate, and any clogging waste it comprises, to a particular maximumsize that is less than a size capable of clogging first-stage anaerobicbioreactor 1200 and/or second-stage anaerobic bioreactor 1400.

In some examples, depending on the substrate (e.g., primarily solidssuch as grass, leaves, wood chips, waste food and organic matter,manure, etc.), container 1020 may include some form of pump or the like,such as an auger or screw pump, that draws raw substrate 722 fromcontainer 1020 and feeds it through conduit 1071 into macerator 1022. Inanother example, macerator 1022 may draw substrate 722 from container1020. In some examples, the specific mechanism(s) responsible for movingthe substrate from container 1020, be it some form of pump and/ormacerator 1022 or the like, is/are controlled by controller 1070.

In some examples, macerated substrate moves intermittently orcontinuously through conduit 1072 into mixer 1026 where a substratemixture is produced; the macerated substrate is typically mixed withwater W from external source 1060 and/or recycled second-stage effluentfrom conduit 1080. In some examples, the rate at which the raw substrate722 flows from container(s) 1020 is also controlled by controller 1070so as to enable the first average flow rate Q₁ of macerated substratebetween macerator 1022 and mixer 1026.

In some examples, mixer 1026 is configured for producing a substratemixture by mixing the macerated substrate with water W from source 1060,which is external to system 1000, and/or with recycled second-stageeffluent from conduit 1080. In this example, water flow into mixer 1026is controlled by controller 1070 via control valve 1043, and effluentflow into mixer 1026 is controlled by controller 1070 via control valve1040. In brief, mixer 1026 is configured to mix at least the substratewith either the water or the second-stage effluent resulting in thesubstrate mixture.

In some examples, the substrate mixture moves intermittently orcontinuously at a second average flow rate Q₂ through conduits 1073,1074, and 1074 b, and through optional heater 1010 f, or through someother suitable configuration, into the first stage of reactor processing1200; for example, into reactor 10 ₁ via substrate inlet 16 ₁. Further,operating under the control of controller 1070, pump 1028 operates underthe control of controller 1070 to induce a second average flow rate Q₂of the mixed substrate into the first stage of reactor processing 1200.

In some examples, heater or heating device 1010 f and conduit 1074 b areoptional. In other examples, heater 1010 f may additionally oralternatively comprise a temperature reducer or cooling device that mayalso be under control of controller 1070. As such, heater 1010 ftypically operates to raise or reduce the temperature of the mixedsubstrate to be substantially similar to that at which the first stageof reactor processing 1200 occurs in reactor 10 ₁. In some examples, themixed substrate is brought to a temperate of within 4 degrees Celsius ofthe first stage processing temperature T_(S1). In brief, the heatingdevice and/or cooling device is configured to bring, prior to feedingthe substrate mixture into first-stage reactor processing system 1200,the temperature of the substrate mixture to substantially thetemperature of the wastewater used in first-stage of reactor processing1200.

Other configurations also fall within the scope and spirit offirst-stage feeding system 1100. For example, maceration may beperformed external to system 1000 so as to eliminate the need formacerator 1022 in system 1000. In other examples, each of one or morecontainers 1020 may be coupled to its own macerator from which thecorresponding macerated substrates are moved into mixer 1026. Further,other configurations also fall within the scope and spirit of theinvention.

Further, first-stage feeding system 1100 and/or one or more of itscomponents may be packaged along with or largely separate from theremainder of system 1000 or any of its other subsystems. The term“packaged” as used herein refers to being mounted on a platform or thelike or contained in a container or the like, where such platforms andcontainers are not permanent additions to or betterments of realproperty that enhance its capital value. For example, first-stagefeeding system 1100 may be contained in one container while first-stagereactor processing system 1200 may be contained in a separate container.Thus, in order to operate together, the two separate systems in theirrespective containers may be brought within proximity to one another andcoupled together via conduits, wires, etc., as required for operation.

First-stage reactor processing system 1200. In general, under thecontrol of controller 1070, this system performs the function ofdigesting the substrate fed into the system 1200 resulting in theproduction of first-stage effluent and biogas. In general, thefirst-stage reactor system 1200 is configured and largely operates asdescribed with respect to reactor 10 above, with at least the followingadditions and/or changes.

FIG. 12 is a schematic diagram that highlights components of thefirst-stage reactor processing system 1200 illustrated in FIG. 10. Insome examples, this system comprises reactor 10 ₁, inlet 66 ₁, heater1010 ₁, pH sensors 1012 _(1L) (where ‘L’ means “lower”) and 1012 _(1U)(where ‘U’ means “upper”), pressure sensor 1002 ₁, and loading port 1036₁. In brief, first-stage reactor processing system 1200 is typicallyconfigured to process a substrate mixture via anaerobic digestionresulting in first-stage effluent. Further, first-stage reactorprocessing system 1200 is typically configured for processing thesubstrate mixture in wastewater 14 ₁ that is maintained by controller1070 at a temperature of between 25 and 65 degrees Celsius.

In some examples, reactor 10 ₁ includes one or more heaters 1010 ₁ ofdifferent or similar types positioned within or without vessel 12 ₁ inany suitable location(s) and configuration(s) so as to enable controller1070 to detect and control the temperature of wastewater 14 ₁ as it isbeing processed by reactor 10 ₁. In one embodiment, controller 1070maintains temperature T_(S1) between 70 and 80 degrees Celsius. In thisembodiment, substrate fed into the first-stage reactor system 1200largely comprises organic green waste or other such fibrous wastes, foodwastes, or manures.

In some examples, reactor 10 ₁ includes the components and performs thefunctions of reactor 10 as described above. In the same or otherexamples, reactor 10 ₁ further includes one or more upper and lower pHsensors 1012 _(1U) and 1012 _(1L) respectively. Both sensors are mountedin vessel 12 ₁ so as to be able to detect the pH of wastewater 14 ₁ andto be coupled to controller 1070. In one embodiment, upper sensor 1012_(1U) is positioned so as to detect the pH of wastewater 14 ₁ abovesludge bed 730 ₁ at the “upper-midpoint,” which is substantiallyhalf-way between septum 20 ₁ and the anticipated location of the upperportion of sludge bed 730 ₁ during operation of reactor 10 ₁. In thisembodiment, lower sensor 1012 _(1L) is positioned so as to detect the pHof wastewater 14 ₁ below sludge bed 730 ₁ at the “lower-midpoint,” whichis substantially half-way between substrate inlet 16 ₁ and theanticipated location of the lower portion of sludge bed 730 ₁ duringoperation of reactor 10 ₁. In brief, upper pH sensor 1012 _(1U) istypically configured to detect the pH of wastewater 14 ₁ above sludgebed 730 ₁ in reactor 10 ₁; and lower pH sensor 1012 _(1L) is typicallyconfigured to detect the pH of wastewater 14 ₁ below the sludge bed 730₁ in reactor 10 ₁.

In some examples, reactor 10 ₁ includes an inlet 66 ₁ in vessel 12 ₁that is located between the lower-midpoint and substrate inlet 16 ₁.This inlet is typically used by pH balancing system 1500. In otherexamples, inlet 66 ₁ is located at other locations in vessel 12 ₁.

In some examples, reactor 10 ₁ includes a pressure sensor 1036 ₁ that islocated at or near the top of vessel 12 ₁, above wastewater 14 ₁. Thissensor is mounted in vessel 12 ₁ so as to enable controller 1070 tomonitor the pressure inside vessel 12, above wastewater 14 ₁.

In some examples, reactor 10 ₁ includes a loading port 1036 ₁ that islocated in or near the top of vessel 12 ₁, above wastewater 14 ₁. Thisport is typically used to load starter bacteria into reactor 10 ₁. Theterm “starter bacteria” as used herein refers to select strains ofbacteria and/or other microorganisms helpful to improving the efficacy,efficiency or stability of a bioreactor. In some examples, this portincludes a lid that, when properly closed, seals the port. The port mayinclude a sensor that enables controller 1070 to detect whether or notthe lid is properly closed and/or sealed.

Further, first-stage reactor processing system 1200 may be packagedalong with or largely separate from the remainder of system 1000 or anyof its other subcomponents.

Second-stage feeding system 1300. In general, under the control ofcontroller 1070, this system performs the function of preparing theeffluent from stage-one reactor processing 1200 and feeding it assubstrate into the second stage of reactor processing 1400. Effluentpreparation may optionally include adjusting the temperature of thefirst-stage effluent to be substantially the same as the second-stageprocessing temperature. The prepared substrate is then pumped orotherwise moved into second-stage reactor 10 ₂.

FIG. 13 is a schematic diagram that highlights components ofsecond-stage feeding system 1300 illustrated in FIG. 10. In someexamples, this system comprises conduit 1075, reducer 1027, conduit1076, pump 1029, and conduit 1077. Conduit 1075 typically coupleseffluent outlet 56 ₁ to reducer 1027, which typically operates under thecontrol of controller 1070 and is optional in some embodiments.Otherwise, reducer 1027 may additionally or alternatively comprise aheater that may also operate under the control of controller 1070. Assuch, reducer 2027 may operate to reduce or raise as necessary thetemperature of the effluent coming from reactor 10 ₁ to be substantiallysimilar to that at which the second stage of reactor processing 1400occurs in reactor 10 ₂. In some examples, the effluent is brought to atemperature of within 4 degrees Celsius of the second stage processingtemperature T_(S2).

In some examples, conduit 1076 couples the output of reducer 1027 to theinlet of pump 1029. In embodiments without reducer 1027, conduit 1075typically couples effluent outlet 56 ₁ to pump 1029, which operatesunder the control of controller 1070 to induce a third average flow rateQ₃ sufficient to move, intermittently or continuously, the first-stageeffluent from reactor 10 ₁ into the second stage of reactor processing1400; for example, into reactor 10 ₂ via substrate inlet 16 ₂.

Other configurations also fall within the scope and spirit ofsecond-stage feeding system 1300. For example, pump 1029 may not berequired due to, inter alia, the relative sizes of vessels 12 ₁ and 12 ₂and/or the relative volumes of wastewater 14 ₁ and 14 ₂. In otherexamples, pump 1029 may be located before or after reducer 1027, orintegrated within reducer 1027, if a reducer used. In other examples,neither reducer 1027 nor pump 1029 is required and effluent outlet 56 ₁is coupled directly, or via a flow controller, to substrate inlet 16 ₂.In other examples, reducer 1027 or pump 1029, either optional, may be orinclude a flow controller. Such a flow control device may not includepumping functionality or heating or cooling functionality, but flowcontrol functionality instead.

Further, second-stage feeding system 1300 may be packaged along with orseparately from system 1000 or its other subsystems. In one example,system 1300 may be packaged in full or in part with subsystems 1100,1200, and/or 1400.

Second-stage reactor processing system. In general, under the control ofcontroller 1070, this system performs the function of digesting thefirst-stage effluent (the processed substrate) fed into the systemresulting in the production of biogas and second-stage effluent that isdifferent than the first-stage effluent. In general, the second-stagereactor system 1400 is configured and operates as described above withrespect to reactor 10 above, with at least the following additionsand/or changes.

FIG. 14 is a schematic diagram that highlights components of thesecond-stage reactor processing system 1400 illustrated in FIG. 10. Insome examples, this system comprises reactor 10 ₂, heater 1010 ₂, pH(“potential of hydrogen”) sensors 1012 _(2L) (where ‘L’ means “lower”)and 1012 _(2U) (where ‘U’ means “upper”), and loading port 1036 ₂. Ingeneral, the second-stage reactor system is configured and operates asdescribed above with respect to reactor 10, with the followingadditions. In brief, second-stage reactor processing system 1400 istypically configured to process the first-stage effluent via anaerobicdigestion resulting in second-stage effluent that is different than thefirst-stage effluent. Further, second-stage reactor processing system1400 is typically configured for processing the substrate mixture inwastewater 14 ₂ that is maintained by controller 1070 at a temperatureof between 70 and 80 degrees Celsius.

In some examples, reactor 10 ₂ includes one or more heaters 1010 ₂ ofdifferent or similar types positioned within or without vessel 12 ₂ inany suitable location(s) and configuration(s) so as to enable controller1070 to detect and control the temperature of wastewater 14 ₂ as it isbeing processed by reactor 10 ₂. In one embodiment, controller 1070maintains temperature T_(S2) between 25 and 65 degrees Celsius, oralternatively between 55 and 60 degrees Celsius. In this embodiment, thesubstrate fed into the second-stage reactor system comprises largely ofthe processed first-stage effluent from reactor 10 ₁.

In some examples, reactor 10 ₂ includes the components and performs thefunctions of reactor 10 as described above. In the same or otherexamples, reactor 10 ₂ also includes one or more upper and lower pHsensors 1012 _(2U) and 1012 _(2L) respectively. Both sensors are mountedin vessel 12 ₂ so as to be able to detect the pH of wastewater 14 ₂ andto be coupled to controller 1070. In one embodiment, upper sensor 1012_(2U) is positioned so as to detect the pH of wastewater 14 ₂ abovesludge bed 730 ₂ at the “upper-midpoint,” which is substantiallyhalf-way between septum 20 ₂ and the anticipated location of the upperportion of sludge bed 730 ₂ during operation of reactor 10 ₂. In thisembodiment, lower sensor 1012 _(2L) is positioned so as to detect the pHof wastewater 14 ₂ below sludge bed 730 ₂ at the “lower-midpoint,” whichis substantially half-way between substrate inlet 16 ₂ and theanticipated location of the lower portion of sludge bed 730 ₂ duringoperation reactor 10 ₂. In brief, upper pH sensor 1012 _(2U) istypically configured to detect the pH of wastewater above the sludge bedin reactor 10 ₂; and the lower pH sensor 1012 _(2L) is typicallyconfigured to detect the pH of wastewater below the sludge bed inreactor 10 ₂.

In some examples, reactor 10 ₂ includes an outlet 67 ₂ in vessel 12 ₂that is located between the lower-midpoint and substrate inlet 16 ₂.This outlet is typically used by pH balancing system 1500.

In some examples, reactor 10 ₂ includes a pressure sensor 1036 ₂ that islocated at or near the top of vessel 12 ₂ above wastewater 14 ₂. Thissensor is mounted in vessel 12 ₂ so as to enable controller 1070 tomonitor the pressure above wastewater 14 ₂ inside vessel 12 ₂.

In some examples, reactor 10 ₂ includes a loading port 1036 ₂ that islocated in or near the top of vessel 12 ₂ and above wastewater 14 ₂.This port is typically used to load starter bacteria into reactor 10 ₂.In some examples, this port includes a lid that, when properly closed,seals the port. The port may include a sensor that enables controller1070 to detect whether or not the lid is properly closed.

Further, second-stage reactor processing system 1400 may be packagedalong with or largely separate from the remainder of system 1000 or anyof its other subcomponents.

Other configurations also fall within the scope and spirit ofsecond-stage reactor processing system 1400 and first-stage reactorprocessing system 1200. For example, in some embodiments, the firststage of reactor processing may be performed by a plurality of reactorssuch as reactor 10 ₁ that are configured to operate in parallel witheach other. In other embodiments, the second stage of reactor processingmay be performed by a plurality of reactors such as reactor 10 ₂ thatare configured to operate in parallel. The phrase “operate in parallel”as used herein means that processed substrate is fed into eachfirst-stage parallel reactor's substrate inlet 16, although the inletsare not necessary directly connected to each other, and that for a givenstage the processed effluent from each reactor's effluent outlet 56 isfed to the next stage, although these outlets are not necessary directlyconnected to each other, where in a two-stage example the next stage isthe second stage if the effluent is coming from first stage of reactorprocessing system 1200, or the next stage is effluent recirculationsystem 1600 if the effluent is coming from second stage of reactorprocessing system 1400.

Further, systems with more than two stages of reactor processing arealso within the scope and spirit of the invention. For example, amulti-stage processing system may include any number of stages ofreactor processing, each operating under the control of controller 1070and/or under the control of its own controller, where the effluent fromeach stage is, with optional processing, fed into the next reactorprocessing stage, and where the final-stage effluent is recirculated byeffluent recirculation system 1600 to one or more prior stages. Eachstage in such a system may process its substrate at any temperaturerequired for the substrate being processed. The gases resulting fromeach stage may be managed as required by the characteristics of eachgas. Further, any stage in a multi-stage processing system may includeone, two, or more reactors operating in parallel as described above. Insome examples, the number of parallel reactors at a parallel stage maybe based at least in part on the digestion rate of the substrate beingprocessed at that stage relative to the digestion rates of substrate atneighboring stages (the stage before and the stage after) of such asystem.

Regarding the phrases “first-stage” and “second-stage” as used herein,including in the claims, these phrases do not limit the stages to beingstage one and stage two respectively in a two-stage or multi-stagesystem. Instead, these terms are simply relative to each other and, forexample, may refer to a first-stage reactor in a series of stages thatsimply comes before a second stage in the same series, where the seriescomprises two or more stages. For example, in a two stage system, afirst-stage reactor is a stage one reactor and a second-stage reactor isa stage two reactor because there are only two reactors in the system.But in another example of a five stage system, a first-stage reactor maybe the stage three reactor and a second-stage reactor may be the stagefour reactor, so long as the second-stage reactor is a stage in theseries that comes after the stage-two reactor in the series. In anotherexample, there may be any number of reactor stages between a stage-onereactor and a stage-two reactor. The same applies to feeding systemsstages and any other subsystem referred to by stage.

PH balancing system 1500. In general, under the control of controller1070, this system 1500 performs the function of maintaining a properrange of pH in wastewater 14 ₁ below sludge bed 730 ₁ in first-stagereactor 10 ₁. Additionally or alternatively, similar systems may beutilized for other stages of reactor processing.

FIG. 15 is a schematic diagram that highlights components of pHbalancing system 1500 illustrated in FIG. 10. In some examples, pHbalancing system 1500 comprises conduit 1083, control valve 1041,conduit 1082, pH sensors 1012 _(1U) and 1012 _(1L) of reactor 10 ₁, andpH sensors 1012 _(2U) and 1012 _(2L) of reactor 10 ₂.

Control valve 1041 typically operates under the control of controller1070. In other examples, control valve 1041 may be or include a pumpand/or flow rate control device that operates under the control ofcontroller 1070 so as to enable controller 1070 to pump and/or controlthe flow or rate of flow of wastewater 14 ₂ from reactor 10 ₂ intoreactor 10 ₁. The specific components employed in subsystem 1500 may bebased on, inter alia, the relative sizes of vessels 12 ₁ and 12 ₂ and/orthe relative volumes of wastewater 14 ₁ and 14 ₂. Note that the effluentfrom any reactor 10 is typically the same that reactor's wastewater 14that is located above sludge bed 730. Thus, as used herein, the effluentfrom a particular reactor is considered the same as the wastewater 14 ofthat particular reactor that is above sludge bed 730.

In brief, pH balancing system 1500 is configured to detect the pH ofwastewater above and below sludge bed 730 in each reactor 10, and tomove or vary the flow of, based on the detected pH values, effluent orwater into the first-stage reactor 10 ₁ under sludge bed 730 ₁.Additionally or alternatively, pH balancing system 1500 may beconfigured to reduce, based on the detected pH values, the flow rate ofsubstrate into the first-stage reactor 10 ₁. Further, control valve 1041is typically configured to enable movement of first-stage effluent orsecond-stage effluent or water into first-stage reactor 10 ₁ undersludge bed 730 ₁.

Further, other conduit and control valve configurations also fall withinthe scope and spirit of the invention. In one example, the inlet side ofconduit 1083 may alternatively be coupled to effluent outlet 56 ₁ ofrector 10 ₁, or conduit 1075, instead of outlet 67 ₂ of reactor 10 ₂. Inother examples, system 1000 may include stores of acidic and/or alkalinechemicals or materials that, under the control of controller 0170, maybe pumped, moved, or fed into any reactor at any location in the reactorso as to manage the pH at the location.

In some examples, pH balancing system 1500 may also include and/orutilize elements of effluent recirculation system 1600. For example,under the control of controller 1070, second-stage effluent may be fedinto reactor 10 ₁ either directly via inlet 66 ₁ or indirectly throughfirst-stage feeding system 1100. In yet another example, water W can befed from source 1060 into reactor 10 ₁ either directly via inlet 66 ₁ orindirectly through first-stage feeding system 1100.

Other configurations also fall within the scope and spirit of pHbalancing system 1500. Further, the various components of pH balancingsystem 1500 may be packaged with system 1000 as a whole or may bedivided up and packaged with other subsystems of system 1000.

Effluent recirculation system 1600. In general, under the control ofcontroller 1070, this system performs the function of recirculatingsecond-stage effluent within and draining excess second-stage effluentfrom system 1000.

FIG. 16 is a schematic diagram that highlights components of effluentrecirculation system 1600 illustrated in FIG. 10. In some examples, thissystem comprises conduit 1078, control valve 1042, conduit 1079, controlvalve 1040, and conduit 1080. Control valve 1040 is typically operatedby controller 1070 so as to enable controller 1070 to allow the flow ofeffluent from reactor 10 ₂ into mixer 1026. In other examples, controlvalve 1040 may be or include a pumping mechanism and/or flow ratecontrol mechanism that operates under the control of controller 1070 soas to enable controller 1070 to pump, move, or control the flow or rateof flow of effluent from reactor 10 ₂ into mixer 1026. In brief,effluent recirculation system 1600 is configured to recirculatesecond-stage effluent by mixing at least the second-stage effluent withsubstrate resulting in a substrate mixture.

Control valve 1042 is typically operated by controller 1070 so as toenable controller 1070 to drain excess effluent from reactor 10 ₂ out ofsystem 1000 via conduit 1079.

Other configurations also fall within the scope and spirit of effluentrecirculation system 1600. Further, the various components of effluentrecirculation system 1600 may be packaged with system 1000 as a whole ormay be divided up and packaged with other subsystems of system 1000.

Gas management system 177. In general, under the control of controller1070, this system 1700 performs the function of managing the gasproduced by system 1000. In some examples, the gas produced may besuitable for use as a biofuel. In other examples, the gas produced byone or more of the reactor stages of system 1000 may be unsuitable foruse as a biofuel.

FIG. 17 is a schematic diagram that highlights components of gasmanagement system 1700 illustrated in FIG. 10. In some examples, system1700 comprises conduit 1090, control valve 1045, conduit 1090 b, conduit1091, control valve 1044, conduit 1092, optional biogas generator 1050,and conduit 1093. Control valve 1045 is typically operated by controller1070 so as to allow controller 1070 to vent the flow of biogas generatedby reactor 10 ₁. In one example, venting biogas flows out of gas outlet46 ₁ via conduit 1090, through control valve 1045, and out of system1000 via conduit 1090 b. In another example, if the biogas is suitable,control valve 1045 may vent the biogas to conduit 1092 where it may beconsumed by generator 1050.

Control valve 1044 is typically operated by controller 1070 so as toallow controller 1070 to vent the flow of biogas generated by reactor 10₂. In one example, venting biogas flows out of gas outlet 46 ₂ viaconduit 1091, through control valve 1044, and through conduit 1092 whereit can be consumed by generator 1050. In another example, if the biogasis unsuitable, control valve 1045 may vent the biogas out of system1000. Exhaust from generator 1050 may be vented from system 1000 viaconduit 1093.

Other configurations also fall within the scope and spirit of gasmanagement system 1700. In one example, biogas that is suitable may becompressed into storage tanks or conditioned and pumped into the publicnatural gas utility system or a renewable natural gas (“RNG”) facility.In another example, suitable biogas produced by system 1000 may be usedas the source of energy for heaters 1010 and the like, thus reducingexternal energy requirements for system 1000. Further, the variouscomponents of gas management system 1700 may be divided up and packagedalong with other subsystems of system 1000.

Further, the various components of gas management system 1700 may bepackaged with system 1000 as a whole or may be divided up and packagedwith other subsystems of system 1000.

Controller. In general, controller 1070 performs the function ofcontrolling, monitoring, and operating system 1000. Such includesproviding external communication between controller 1070 and externalcomputing devices and systems via various types of connectivitymechanisms 1071, which may include wired and wireless networks,communication buses such as universal serial bus (“USB”) and others, andany other suitable communication mechanisms.

In some examples, such external communication capabilities enable remotecomputing devices and the like (e.g., as illustrated in FIG. 18) toremotely monitor system 1000 and its subsystems, components, sensors,operating status, etc. The external communication capabilities furtherenable remote administrators (persons and other entities sufficientlycapable), when authorized, to, for example, start system 1000, shut itdown, override any automatic control initiated by controller 1070,change its operating mode, etc. In some examples, operating modesinclude: Shut Down, Starting, Operational, Standby, Shutting Down,System Test, and System Error.

Controller 1070 is typically coupled internally to components of system1000 that provide sensor data and that can be automatically controlled.Such internal couplings may be digital, analog, wired, wireless, anycombination of the foregoing, or any other kind suitable. Such internalcouplings are illustrated in the figures by dashed lines 1052, butadditional or different internal couplings, other internal couplingconfigurations, and couplings between packaged subsystems of system 1000are also within the scope and spirit of the invention. It is via theseinternal couplings that controller 1070 monitors and receives sensorinformation and the like, and by which it controls controllablecomponents and the like. Various components may include sensors or thelike as well as controllable functionality. For example, a heatercomponent may be controlled by controller 1070 and also providetemperature sensor information back to controller 1070.

In some examples, controller 1070 is coupled to sensors and, accordingto the various capabilities of the sensors, is configured to detect,measure, and/or monitor the presence, level, amount, weight, volume,mass, or the like of materials (such as, for example, raw substrate incontainer(s) 1020, wastewater 14 in reactors, etc), and/or variouscharacteristics of the materials (including, but not limited to,temperature, pressure, solids concentration, pH, flow, flow rate,turbulence, acidity, alkalinity, corrosiveness, abrasiveness, viscosity,vibration, and any other characteristics relevant to system 1000), thematerials being processed, and the materials resulting from suchprocessing. Via the same or other sensors, controller 1070 may alsodetect, monitor, read, receive, or the like data or informationregarding any of the components of system 1000 where such data orinformation is made available by sensors separate from the components orby the components themselves. Non-limiting examples of such sensorsinclude those that are part of or associated with system 1000'scontainer(s), macerator(s), mixer(s), control valves, pumps, heaters,reducer(s), communication mechanisms, and any others.

In some examples, controller 1070 is coupled to various components and,according to the various capabilities of the components, is configuredto detect, control, and/or monitor the operation and/or characteristicsof each, and/or the presence, level, amount, weight, volume, or the likeof material contained in, being processed by, or flowing through each,and/or the operation, force, function, flow rate, or other capabilitiesof each. Detectable characteristics for each such component may include,but are not limited to, its unique identifier, capacities, capabilities,configuration, its available information and the information itself,operating status, power status, component identification and status, andthe like. Non-limiting examples of such components include those ofsystem 1000: container(s), macerator(s), mixer(s), control valves,pumps, heaters, reducer(s), communication mechanisms, and any others.

Further, controller 1070 may be packaged along with system 1000 or anyof its separately-packaged subsystems or remotely from system 1000 andits subsystems.

FIG. 18 is a block diagram showing an example computing environment 100in which variations of controller 1070 may be implemented. A suitablecomputing environment may be implemented with any of numerous generalpurpose or special purpose devices and/or systems. Examples of suchdevices/systems include, but are not limited to, computer-basedcontrollers, personal digital assistants (“PDA”), personal computers(“PC”), hand-held or laptop devices, microprocessor-based systems,multiprocessor systems, systems on a chip (“SOC”) servers, Internetservices, workstations, consumer electronic devices, cell phones, andthe like. In all cases, such systems are strictly limited to beingarticles of manufacture and the like. Different variations of controller1070 may include different combination of the above and below describeddevices, systems, and components.

Computing environment 1800 typically includes at least one computingdevice 1801 coupled to various components, such as peripheral devices1802, 1803, 1801 and the like. These may include components such asinput devices 1803 such as voice recognition technologies, touch pads,buttons, keyboards and/or pointing devices, such as a mouse ortrackball, that may operate via one or more input/output (“I/O”)interfaces 1812. The components of computing device 1801 may include oneor more processors (including central processing units (“CPU”), graphicsprocessing units (“GPU”), microprocessors (“μP”), and the like) 1807,system memory 1809, and a system bus 1808 that typically couples thevarious components. Processor(s) 1807 typically processes or executesvarious computer-executable instructions and, based on thoseinstructions, controls the operation of computing device 1801. This mayinclude the computing device 1801 communicating with other electronicand/or computing devices, systems or environments (not shown) viavarious communications technologies such as a network connection 1814 orthe like. System bus 1808 represents any number of bus structures,including a memory bus or memory controller, a peripheral bus, a serialbus, an accelerated graphics port, a processor or local bus using any ofa variety of bus architectures, and the like.

System memory 1809 may include computer-readable media in the form ofvolatile memory, such as random access memory (“RAM”), and/ornon-volatile memory, such as read only memory (“ROM”) or flash memory(“FLASH”). A basic input/output system (“BIOS”) may be stored innon-volatile or the like. System memory 1809 typically stores data,computer-executable instructions and/or program modules comprisingcomputer-executable instructions that are immediately accessible toand/or presently operated on by one or more of the processors 1807. Theterm “system memory” as used herein refers strictly to a physicalarticle(s) of manufacture or the like.

Mass storage devices 1804 and 1810 may be coupled to computing device101 or incorporated into computing device 1801 via, for example,coupling to the system bus. Such mass storage devices 1804 and 1810 mayinclude non-volatile RAM, a magnetic disk drive which reads from and/orwrites to a removable, non-volatile magnetic disk (e.g., a “floppydisk”) 1805, and/or an optical disk drive that reads from and/or writesto a non-volatile optical disk such as a CD ROM, DVD ROM 1806.Alternatively, a mass storage device, such as hard disk 1810, mayinclude non-removable storage medium. Other mass storage devices mayinclude memory cards, memory sticks, tape storage devices, and the like.The term “mass storage device” as used herein refers strictly to aphysical article(s) of manufacture or the like.

Any number of computer programs, files, data structures, control logic,computer-executable instructions, and the like may be stored in massstorage 1810, other storage devices 1804, 1805, 1806 and system memory1809 (typically limited by available space) including, by way of exampleand not limitation, operating systems, application programs, data files,directory structures, computer-executable instructions, and the like.

Output components or devices, such as display device 1802, may becoupled to computing device 1801, typically via an interface such as adisplay adapter 1811. Output device 1802 may be a liquid crystal display(“LCD”). Other example output devices may include printers, audiooutputs, voice outputs, cathode ray tube (“CRT”) displays, tactiledevices or other sensory output mechanisms, or the like. Output devicesmay enable computing device 1801 to interact with human operators orother machines, systems, computing environments, or the like. A user mayinterface with computing environment 100 via any number of different I/Odevices 1803 such as a touch pad, buttons, keyboard, mouse, joystick,game pad, data port, and the like. These and other I/O devices may becoupled to processor(s) 1807 via I/O interfaces 1812 which may becoupled to system bus 1808, and/or may be coupled by other interfacesand bus structures, such as a parallel port, game port, universal serialbus (“USB”), fire wire, infrared (“OR”) port, and the like.

Computing device 1801 may operate in a networked environment viacommunications connections to one or more remote computing devicesthrough one or more cellular networks, wireless networks, local areanetworks (“LAN”), wide area networks (“WAN”), storage area networks(“SAN”), the Internet, radio links, optical links and the like.Computing device 1801 may be coupled to a network via network adapter1813 or the like, or, alternatively, via a modem, digital subscriberline (“DSL”) link, integrated services digital network (“ISDN”) link,Internet link, wireless link, or the like.

Communications connection 1814, such as a network connection, typicallyprovides a coupling to communications media, such as a network.Communications media typically provide computer-readable andcomputer-executable instructions, data structures, files, programmodules and other data using a modulated data signal, such as a carrierwave or other transport mechanism. The term “modulated data signal”typically means a signal that has one or more of its characteristics setor changed in such a manner as to encode information in the signal.Byway of example, and not limitation, communications media may includewired media, such as a wired network or direct-wired connection or thelike, and wireless media, such as acoustic, radio frequency, infrared,or other wireless communications mechanisms.

Power source 1890, such as a battery or a power supply, typicallyprovides power for portions or all of computing environment 1800. In thecase of the computing environment 1800 being a mobile device or portabledevice or the like, power source 1890 may be a battery. Alternatively,in the case computing environment 1800 is a desktop computer or serveror the like, power source 1890 may be a power supply designed to connectto an alternating current (“AC”) source, such as via a wall outlet.

Some mobile devices or controllers may include only a few of thecomponents described in connection with FIG. 18. For example, controller1070 may not include a built-in display, keyboard, or otherhuman-interface devices. But such a controller may include communicationmechanisms that facilitate the controller's interaction, local and/orremote, with other more conventional computing devices. Such interactionor communication may be via various kinds of local buses (e.g., USB orthe like) and/or via wireless or wired networks include via theInternet.

Those skilled in the art will realize that storage devices utilized toprovide computer-readable and computer-executable instructions and datacan be distributed over a network. For example, a remote computer orstorage device may store computer-readable and computer-executableinstructions in the form of software applications and data. A localcomputer may access the remote computer or storage device via thenetwork and download part or all of a software application or data andmay execute any computer-executable instructions. Alternatively, thelocal computer may download pieces of the software or data as needed, ordistributively process the software by executing some of theinstructions at the local computer and some at remote computers and/ordevices.

Those skilled in the art will also realize that, by utilizingconventional techniques, all or portions of the software'scomputer-executable instructions may be carried out by a dedicatedelectronic circuit such as a digital signal processor (“DSP”),programmable logic array (“PLA”), discrete circuits, and the like. Theterm “electronic apparatus” may include computing devices or consumerelectronic devices comprising any software, firmware or the like, orelectronic devices or circuits comprising no software, firmware or thelike.

The term “firmware” as used herein typically includes and refers toexecutable instructions, code, data, applications, programs, programmodules, or the like maintained in an electronic device such as a ROM.The term “software” as used herein typically includes and refers tocomputer-executable instructions, code, data, applications, programs,program modules, firmware, and the like maintained in or on any form ortype of computer-readable media that is configured for storingcomputer-executable instructions or the like in a manner that may beaccessible to a computing device.

The terms “computer-readable medium”, “computer-readable media”, and thelike as used herein and in the claims are limited to referring strictlyto one or more statutory apparatus, machine, article of manufacture, orthe like that is not a signal or carrier wave per se. Thus,computer-readable media, as the term is used herein, is intended to beand shall be interpreted as statutory subject matter.

The term “computing device” as used herein and in the claims is limitedto referring strictly to one or more statutory apparatus, article ofmanufacture, or the like that is not a signal or carrier wave per se,such as computing device 1801 that encompasses client devices, mobiledevices, one or more servers, network services such as an Internetservices or corporate network services based on one or more computers,and the like, and/or any combination thereof. Thus, a computing device,as the term is used herein, is also intended to be and shall beinterpreted as statutory subject matter.

Nitrogen reduction. In general, substrate that is rich in nitrogencompounds, particularly ammonia, tends to inhibit the anaerobicdigestion process typically performed by system 1000. Such inhibitionmay be referred to as nitrogen toxicity or ammonia toxicity. The term“nitrogen compounds” as used herein includes but is not limited toorganic and inorganic nitrogen, ammonia, ammonium, nitrates, andnitrites. In one example, poultry manure may be sufficiently rich innitrogen compounds so as to inhibit the anaerobic digestion process. Theterm “nitrogen-rich substrate” as used herein typically refers to asubstrate with an ammonia concentration sufficient to inhibit theanaerobic digestion process typically performed by system 1000. In oneexample, a substrate with an ammonia concentration in excess of aboutthree thousand (3,000) parts per million (ppm) is sufficientlynitrogen-rich to inhibit the anaerobic digestion process performed bysystem 1000. In another example, a substrate with an ammoniaconcentration in excess of about six thousand (6,000) ppm issufficiently nitrogen-rich to inhibit the anaerobic digestion processperformed by system 1000. The term “nitrogen compound” as used hereintypically includes any organic and inorganic compound that includesnitrogen, including but not limited to ammonia, ammonium, nitrates, andnitrites in their various forms.

Nitrogen reduction systems. In order to minimize the inhibiting effectsof nitrogen-rich substrate on system 1000, one or more nitrogenreduction systems may be employed that are configured to reduce theamount of one or more nitrogen compounds in a substrate or a substratemixture. In some examples, the amount of nitrogen is reduced below atoxicity threshold. In one such example, the toxicity threshold for oneor more nitrogen compounds is about three thousand (3,000) ppm. Inanother such example, the toxicity threshold for one or more nitrogencompounds is about six thousand (6,000) ppm. In other examples, one ormore nitrogen compounds in a substrate mixture may be reduced by anitrogen reduction system sufficient to result in uninhibited anaerobicdigestion by system 1000 based on one or more factors other than, orincluding, a particular toxicity threshold. In some examples, suchfactors may include a pH of the substrate mixture, a flow rate (e.g., Q₁or Q₂), a rate at which gas is produced (e.g., methane or hydrogen), orother factors detectable and/or controllable by controller 1070.

In some examples, a nitrogen reduction system reduces the amount of oneor more nitrogen compounds in a substrate mixture sufficient toprocedure a non-toxic substrate mixture. The term “non-toxic substratemixture” as used herein refers to a substrate mixture with one or morenitrogen compounds being sufficiently low that, for purposes ofanaerobic digestion by system 1000, the anaerobic digestion process isconsidered uninhibited. Stated another way, the non-toxic substratemixture is considered non-toxic with respect to anaerobic digestion ofthe non-toxic substrate by system 1000.

In one example, a nitrogen-rich substrate mixture that has had theamount of ammonia it contains reduced below a toxicity threshold isconsidered a non-toxic substrate mixture. Example nitrogen reductionsystems 1900, 2000, and 2100 described below are examples of systemsconfigured for converting nitrogen-rich substrates or substrate mixturesinto non-toxic substrates or substrate mixtures either before or duringthe anaerobic digestion process typically performed by system 1000.

FIG. 19 is a schematic diagram that illustrates example nitrogenreduction system (“NRS”) 1900 that is configured for reducing an amountof at least one nitrogen compound in a substrate or substrate mixturewithin one or more substrate mixers (such as mixer 1026), resulting in anon-toxic substrate mixture within such mixers.

NRS 1900 comprises mixer 1026 and its association components, controller1070, sparger 1910, sparging control valve 1920, sparging input 1930,optional mixer cover 1940, optional gas collection port 1942, optionalsensor(s) 1944, and optional gas collector 1950. In some examples of NRS1900, mixer 1026 is configured for producing a substrate mixture bymixing macerated substrate with water and/or second-stage effluent asdescribed above, where the macerated substrate includes at least somenitrogen-rich substrate.

NRS 1900 is typically configured to sparge the substrate mixture inmixer 1026. Sparging input 1930 is typically coupled to a source ofsparging gas. In one example, ambient air or any chemically inert gas,or any combination of ambient air and/or such gases, may be used as thesparging gas. In another example, steam may be used as the sparging gas.In yet another example, gas(es) collected in gas collector 1950 may beused as the sparging gas or may be combined with ambient air, inertgas(es), and/or steam and may be used as the sparging gas.

In some examples, the sparging gas flows through sparging control valve1920 and into sparger 1910 under the control of controller 1070 asindicated by the dashed line between the two. In some examples,controller 1070 is configured to enable or disable the flow of thesparging gas into mixer 1026, control the rate at which the sparging gasflows, and/or control the pressure of the sparging gas. Controller 1070may also control the temperature of the sparging gas. In some examples,controller 1070 is also configured to control the temperature of thesubstrate mixture in mixer 1026. In these example, the controller maymaintain the substrate mixture at a temperature of up to about 100degrees Celsius during sparging.

In some examples, sparger 1910 is configured to inject sparging gas intothe substrate mixture in mixer 1026. Sparging may occur while thesubstrate is being mixed and/or while mixing has stopped. In someexamples, at least one sparger 1910 is disposed so as to inject thesparging gas into the substrate mixture from one or more locations at ornear the lower half of mixer 1026. In other examples, sparger 1910 isconfigured to diffuse the sparging gas into and/or throughout thesubstrate mixture in mixer 1026. The verb “inject” in its various formsas used herein typically encompasses the verb “diffuse” in it variousforms as used herein.

In some examples, sensor(s) 1944 represents a pH sensor(s) that detectsthe pH of the substrate mixture in mixer 1026, and is coupled tocontroller 1070 as indicated by the dashed line between the two.Additionally or alternatively, sensor(s) 1944 may also represent anitrogen compound sensor(s) that detects an amount or concentration ofammonia and/or other nitrogen compounds in the substrate mixture.Controller 1070 may obtain the detected pH and/or nitrogen compoundinformation from sensor(s) 1944 and may control NRS 1900 based at leastin part on this information.

In some examples, optional mixer cover 1940 is not used and gasesbubbling to the top of the substrate may be allowed to flow out of themixer. In other examples, cover 1940 is a part of mixer 1026 or is addedto the mixer so as to enable the collection of at least a portion ofgases that bubble up through the substrate mixture as a result of thesparging. In some examples, the collected gases pass through gascollection port 1942 and are collected in gas collector 1950.

NRS 1900 may be used alone in mixer 1026, or in conjunction with NRS2000 and/or NRS 2100.

FIG. 20 is a schematic diagram that illustrates example nitrogenreduction system (“NRS”) 2000 that is configured for reducing an amountof at least one nitrogen compound in a substrate or substrate mixturewithin one or more reactor vessels (such as reactor vessel 12 ₁ and/orreactor vessel 12 ₂), resulting in a non-toxic substrate mixture withinsuch vessels.

NRS 2000 comprises anaerobic bioreactor 10 (which may be first-stageanaerobic bioreactor 10 ₁ and/or second-stage anaerobic bioreactor 10 ₂)along with its associated components (including vessel 12), controller1070, sparger 2010, sparging control valve 2020, sparging input 2030,and sensors 1012.

NRS 2000 is typically configured to sparge the substrate mixture 14 invessel 12. Sparging input 2030 is typically coupled to a source ofsparging gas. In one example, ambient air or any chemically inert gas,or any combination of ambient air and/or such gases, may be used as thesparging gas. In another example, steam may be used as the sparging gas.In yet another example, gas(es) collected in gas collector 1950 may beused as the sparging gas or may be combined with ambient air, inertgas(es), and/or steam and may be used as the sparging gas.

In some examples, the sparging gas flows through sparging control valve2020 and into sparger 2010 under the control of controller 1070 asindicated by the dashed line between the two. In some examples,controller 1070 is configured to enable or disable the flow of thesparging gas into vessel 12, control the rate at which the sparging gasflows, and/or control the pressure of the sparging gas. Controller 1070may also control the temperature of the sparging gas. In some examples,controller 1070 is also configured to control the temperature of thesubstrate mixture 14 in vessel 12. In these example, the controller maymaintain the substrate mixture at a temperature of up to about 100degrees Celsius during sparging.

In some examples, sparger 2010 is configured to inject sparging gas intosubstrate mixture 14 in vessel 12. Sparging of the substrate mixture mayoccur during the anaerobic digestion process within vessel 12 and/orwhile digestion has stopped. In some examples, one or more sparger 2010is disposed so as to inject the sparging gas into the substrate mixturefrom one or more locations at or near the lower half of vessel 12. Inother examples, sparger 2010 is configured to diffuse the sparging gasinto and/or throughout the substrate mixture 14 in vessel 12.

In some examples, sensors 1012 represent pH sensors that detect the pHof the substrate mixture in vessel 12 as described in connection withFIG. 15, and are coupled to controller 1070 as indicated by the dashedline between them. Additionally or alternatively, sensors 1012 may alsorepresent one or more nitrogen compound sensors that detect an amount orconcentration of ammonia and/or other nitrogen compounds in thesubstrate mixture. Controller 1070 may obtain the detected pH and/ornitrogen compound information from sensors 1012 and may control NRS 2000based at least in part on this information.

NRS 2000 may be used alone in first stage anaerobic bioreactor 10 ₁and/or first stage anaerobic bioreactor 10 ₂, or in conjunction with NRS1900 and/or NRS 2100.

FIG. 21 is a schematic diagram that illustrates example nitrogenreduction system (“NRS”) 2100 that is configured for reducing an amountof at least one nitrogen compound in a substrate or substrate mixturewithin one or more pre=processing vessels (such as pre-processing vessel12 _(p)), resulting in a non-toxic substrate mixture within suchvessel(s).

NRS 2100 comprises one or more pre-processing vessels (such as vessel 12_(p)) along with other associated components not shown, controller 1070,sparger 2110, sparging control valve 2120, sparging input 2130, one ormore sensors (such as sensors 2112 _(U) and 2112 _(L)), substratemixture input port 2150, and substrate mixture output port 2140.

In general, NRS 2100 is inserted between a first-stage feeder system,such as system 1100 illustrated in FIG. 11, and a first-stage reactorsystem, such as system 1200 illustrated in FIG. 12. In one example ofsuch an insertion, the output side of conduit 1074 b of system 1100 iscoupled to substrate mixture input port 2150 with substrate mixtureoutput port 2140 coupled to substrate inlet 16 ₁ of system 1200 via asuitable feeder system such as, for example, a system similar to feedersystem 1300 illustrated in FIG. 13.

In one example, NRS 2100 comprises a single vessel 12 _(p). In anotherexample, NRS 2100 comprises a plurality of vessels such as vessel 12_(p) that are coupled together in parallel. In another example, NRS 2100comprises a plurality of vessels such as vessel 12 _(p) that are coupledtogether in series. In yet another example, NRS 2100 comprises aplurality of vessels such as vessel 12 _(p) with a combination ofparallel-coupled and series-coupled vessels.

Substrate mixture input port 2150 is typically located in the bottom orthe lower portion of vessel 12 _(p), but may be located in any suitablelocation. Substrate mixture output port 2140 is typically located in thelower portion of vessel 12 _(p), but may also be located in any suitablelocation.

NRS 2100 is typically configured to sparge the substrate mixture 14 invessel 12 _(p). Sparging input 2130 is typically coupled to a source ofsparging gas. In one example, ambient air or any chemically inert gas,or any combination of ambient air and/or such gases, may be used as thesparging gas. In another example, steam may be used as the sparging gas.In yet another example, gas(es) collected in gas collector 1950 may beused as the sparging gas or may be combined with ambient air, inertgas(es), and/or steam and may be used as the sparging gas.

In some examples, the sparging gas flows through sparging control valve2120 and into sparger 2110 under the control of controller 1070 asindicated by the dashed line between the two. In some examples,controller 1070 is configured to enable or disable the flow of thesparging gas into vessel 12 _(p), control the rate at which the sparginggas flows, and/or control the pressure of the sparging gas. Controller1070 may also control the temperature of the sparging gas.

In some examples, sparger 2110 is configured to inject sparging gas intosubstrate mixture 14 in vessel 12 _(p). In some examples, one or moresparger 2110 is disposed so as to inject the sparging gas into thesubstrate mixture from one or more locations at or near the lower halfof vessel 12. In other examples, sparger 2110 is configured to diffusethe sparging gas into and/or throughout the substrate mixture 14 invessel 12 _(p).

NRS 2100 may include one or more sensors, such as sensors 2112. Suchsensors may be attached to or located through or within vessel 12 _(p)in any suitable location. In some examples, sensors 2112 represent pHsensors that detect the pH of the substrate mixture at one or morelocations in vessel 12 _(p), and are coupled to controller 1070 asindicated by the dashed lines between them. Additionally oralternatively, sensors 2112 may also represent one or more nitrogencompound sensors that each detect an amount or concentration of ammoniaand/or other nitrogen compounds in the substrate mixture. Controller1070 may obtain the detected pH and/or nitrogen compound informationfrom sensors 2112 and may control NRS 2100 based at least in part onthis information.

NRS 2100 may be used alone in one or more pre-processing stages, or inconjunction with NRS 1900 and/or NRS 2000.

Nitrogen reduction method. FIG. 22 is a diagram illustrating examplemethod 2200 for reducing an amount of at least one nitrogen compound ina substrate or substrate mixture resulting in a non-toxic substratemixture for purposes of anaerobic digestion by system 1000. In general,the process of such reducing is known herein as a “nitrogen reductionprocess” which is typically performed by one or more nitrogen reductionsystems such as NRS 1900, 2000, and 2100.

Block 2210 typically indicates producing a substrate mixture asdescribed in connection with FIG. 11. In some examples, the substratemixture comprises nitrogen-rich substrate that is toxic to anaerobicdigestion by system 1000. In some examples, the production of substratemixture continues during other steps of method 2100, subject to controlby controller 1070.

Block 2220 typically indicates injecting or diffusing, by a nitrogenreduction system such as NRS 1900, 2000, or 2100, sparging gas (such asdescribed in connection with FIGS. 19, 20, and/or 21) into the substratemixture. In some examples, the sparging gas is injected or diffused intothe substrate mixture, or a portion thereof, that is located in mixer1026, in vessel 12 ₁ or 12 ₂, and/or in pre-processing vessel 12 _(p).In some examples, the sparging gas flows through a sparging input from asparging gas source, through a sparging control valve, and into asparger under the control of controller 1070, which is configured toenable or disable the flow of the sparging gas, control the rate atwhich the sparging gas flows, control the pressure of the sparging gas,and/or control the temperature of the sparging gas. In some examples,the injection or diffusion of sparging gas into the substrate mixturecontinues during other steps of method 2100, subject to control bycontroller 1070.

Block 2230 typically indicates detecting, by controller 1070, one ormore factors such as an amount or concentration of one or more nitrogencompounds in the substrate mixture, a pH of the substrate mixture, aflow rate (e.g., Q₁ or Q₂), a rate at which gas is produced (e.g.,methane and/or hydrogen), or other factors detectable and/orcontrollable by controller 1070. In some examples, the detecting isperformed in a substantially continuous manner, typically under controlof controller 1070. In other examples, the detecting is performed on aperiodic or on an as-needed basis, typically under control of controller1070. In some examples, the detecting continues during other steps ofmethod 2100, subject to control by controller 1070.

Block 2240 typically indicates controlling, by controller 1070, thenitrogen reduction process. In some examples, such controlling includescontrolling the production of a substrate mixture (e.g., block 2210)and/or the injecting or diffusing of sparging gas into the substratemixture, or a portion thereof, that is located in mixer 1026, in vessel12 ₁ or 12 ₂, and/or in pre-processing vessel 12 _(p) (e.g., block2220), based at least on factors such as those described in connectionwith block 2230. Such controlling may involve the control of one or moreflow rates, pressures, temperatures, the detecting of various factors,and/or other aspects of the processes involved in the operation ofsystem 1000 described herein. In general, such controlling continuesthroughout the nitrogen reduction process.

While this invention has been described with reference to certainspecific embodiments and examples, those skilled in the art willrecognize that many variations are possible without departing from thescope and spirit of this invention. The invention, as defined by theclaims, is intended to cover all changes and modifications of theinvention which do not depart from the spirit of the invention. Thewords “including” and “having,” as used in the specification, includingthe claims, shall have the same meaning as the word “comprising.”

CONCLUSION

In a first example, a multi-stage anaerobic bioreactor processing systemcomprises: a vessel configured for inducing a sludge bed; a mixerconfigured for producing a substrate mixture from at least maceratedsubstrate that includes at least some nitrogen-rich substrate, the mixercomprising a nitrogen reduction system configured for reducing an amountof at least one nitrogen compound in the substrate mixture resulting ina non-toxic substrate mixture for purposes of anaerobic digestion by theIBR system; and at least a portion of a feeder system configured forfeeding at least a portion of the non-toxic substrate mixture into thevessel.

In the first example, the at least one nitrogen compound is ammonia; thenitrogen reduction system is further configured for reducing the amountof the at least one nitrogen compound in the substrate mixture below atoxicity threshold that is six thousand (6,000) parts per million orthree thousand (3,000) parts per million; the nitrogen reduction systemcomprises a sparger coupled to a source of sparging gas and configuredfor injecting the sparging gas into the substrate mixture in the mixer;the nitrogen reduction system comprises a mixer cover, a gas collectionport, and a gas collector, wherein the combination of the mixer, themixer cover, the gas collection port, and the gas collector areconfigured for collecting gasses resulting from injection of sparginggas into the substrate mixture; the nitrogen reduction system is furtherconfigured for recirculating at least a portion of gasses collected inthe gas collector as at least a portion of the sparging gas; and thenitrogen reduction system comprises a sensor that is configured fordetecting a pH of the substrate mixture or an amount or concentration ofa nitrogen compound in the substrate mixture, the sensor coupled to acontroller that is configured for controlling the nitrogen reductionsystem based at least in part on the detected pH of the substratemixture or the amount or concentration of the nitrogen compound in thesubstrate mixture.

In a second example, a multi-stage anaerobic bioreactor processingsystem comprises: a plurality of vessels, at least one of which isconfigured for inducing a sludge bed; a portion of a feeder systemconfigured for feeding a substrate mixture into one of the plurality ofvessels; and the one of the plurality of vessels comprising a nitrogenreduction system configured for reducing an amount of at least onenitrogen compound in the substrate mixture resulting in a non-toxicsubstrate mixture with respect to anaerobic digestion of the non-toxicsubstrate by the IBR system.

In the second example, the at least one nitrogen compound is ammonia;the nitrogen reduction system is further configured for reducing theamount of the at least one nitrogen compound in the substrate mixturebelow a toxicity threshold that is six thousand (6,000) parts permillion or three thousand (3,000) parts per million; the nitrogenreduction system comprises a sparger coupled to a source of sparging gasand configured for injecting the sparging gas into the substrate mixturein the one of the plurality of vessels; the one of the plurality ofvessels is the vessel of a first-stage reactor of the IBR system, thevessel of a second-stage reactor of the IBR system, or the vessel of apre-processing stage of the IBR system; and the nitrogen reductionsystem comprises a sensor that is configured for detecting a pH of thesubstrate mixture or an amount or concentration of a nitrogen compoundin the substrate mixture, the sensor coupled to a controller that isconfigured for controlling the nitrogen reduction system based at leastin part on the detected pH of the substrate mixture or the amount orconcentration of the nitrogen compound in the substrate mixture.

In a third example, a method of reducing an amount of a nitrogencompound within a substrate mixture in an induced bed bioreactor (“IBR”)system comprises: producing, by a mixer of the IBR system, a substratemixture that comprises nitrogen-rich substrate; injecting, by a nitrogenreduction system of the IBR system, sparging gas into at least a portionof the substrate mixture resulting in a non-toxic substrate mixture thatis considered non-toxic with respect to anaerobic digestion of thenon-toxic substrate by the IBR system.

In the third example, the sparging gas is injected into the at least aportion of the substrate mixture that is located within the mixer; thesparging gas is injected into the at least a portion of the substratemixture that is located within a reactor vessel of the IBR system; thesparging gas is injected into the at least a portion of the substratemixture that is located within a pre-processing vessel of the IBRsystem; the nitrogen compound is ammonia; the method further comprisesdetecting, via a sensor of the IBR system, a pH of the at least aportion of the substrate mixture or an amount or concentration of anitrogen compound in the substrate mixture, and controlling, by acontroller of the IBR system, operation of the nitrogen reduction systembased at least in part on the detected pH of the at least a portion ofthe substrate mixture or the amount or concentration of the nitrogencompound in the substrate mixture; and the sparging gas comprisesambient air, a chemically inert gas, or steam.

1. An induced bed bioreactor (“IBR”) system comprising: a vesselconfigured for inducing a sludge bed; a mixer configured for producing asubstrate mixture from at least macerated substrate that includes atleast some nitrogen-rich substrate, the mixer comprising a nitrogenreduction system configured for reducing an amount of at least onenitrogen compound in the substrate mixture resulting in a non-toxicsubstrate mixture for purposes of anaerobic digestion by the IBR system;and at least a portion of a feeder system configured for feeding atleast a portion of the non-toxic substrate mixture into the vessel. 2.The IBR system of claim 1 wherein the at least one nitrogen compound isammonia.
 3. The IBR system of claim 1 wherein the nitrogen reductionsystem is further configured for reducing the amount of the at least onenitrogen compound in the substrate mixture below a toxicity thresholdthat is: six thousand (6,000) parts per million; or three thousand(3,000) parts per million.
 4. The IBR system of claim 1, the nitrogenreduction system comprising a sparger coupled to a source of sparginggas and configured for injecting the sparging gas into the substratemixture in the mixer.
 5. The IBR system of claim 1, the nitrogenreduction system comprising: a mixer cover; a gas collection port; and agas collector; wherein the combination of the mixer, the mixer cover,the gas collection port, and the gas collector are configured forcollecting gasses resulting from injection of sparging gas into thesubstrate mixture.
 6. The IBR system of claim 5, the nitrogen reductionsystem further configured for recirculating at least a portion of gassescollected in the gas collector as at least a portion of the sparginggas.
 7. The IBR system of claim 1, the nitrogen reduction systemcomprising a sensor that is configured for detecting a pH of thesubstrate mixture or an amount or concentration of a nitrogen compoundin the substrate mixture, the sensor coupled to a controller that isconfigured for controlling the nitrogen reduction system based at leastin part on the detected pH of the substrate mixture or the amount orconcentration of the nitrogen compound in the substrate mixture.
 8. Aninduced bed bioreactor (“IBR”) system comprising: a plurality ofvessels, at least one of which is configured for inducing a sludge bed;a portion of a feeder system configured for feeding a substrate mixtureinto one of the plurality of vessels; and the one of the plurality ofvessels comprising a nitrogen reduction system configured for reducingan amount of at least one nitrogen compound in the substrate mixtureresulting in a non-toxic substrate mixture with respect to anaerobicdigestion of the non-toxic substrate by the IBR system.
 9. The IBRsystem of claim 8 wherein the at least one nitrogen compound is ammonia.10. The IBR system of claim 8 wherein the nitrogen reduction system isfurther configured for reducing the amount of the at least one nitrogencompound in the substrate mixture below a toxicity threshold that is:six thousand (6,000) parts per million; or three thousand (3,000) partsper million.
 11. The IBR system of claim 8, the nitrogen reductionsystem comprising a sparger coupled to a source of sparging gas andconfigured for injecting the sparging gas into the substrate mixture inthe one of the plurality of vessels.
 12. The IBR system of claim 8wherein the one of the plurality of vessels is: the vessel of afirst-stage reactor of the IBR system; the vessel of a second-stagereactor of the IBR system; or the vessel of a pre-processing stage ofthe IBR system.
 13. The IBR system of claim 8, the nitrogen reductionsystem comprising a sensor that is configured for detecting a pH of thesubstrate mixture or an amount or concentration of a nitrogen compoundin the substrate mixture, the sensor coupled to a controller that isconfigured for controlling the nitrogen reduction system based at leastin part on the detected pH of the substrate mixture or the amount orconcentration of the nitrogen compound in the substrate mixture.
 14. Amethod of reducing an amount of a nitrogen compound within a substratemixture in an induced bed bioreactor (“IBR”) system, the methodcomprising: producing, by a mixer of the IBR system, a substrate mixturethat comprises nitrogen-rich substrate; injecting, by a nitrogenreduction system of the IBR system, sparging gas into at least a portionof the substrate mixture resulting in a non-toxic substrate mixture thatis considered non-toxic with respect to anaerobic digestion of thenon-toxic substrate by the IBR system.
 15. The method of claim 14wherein the sparging gas is injected into the at least a portion of thesubstrate mixture that is located within the mixer.
 16. The method ofclaim 14 wherein the sparging gas is injected into the at least aportion of the substrate mixture that is located within a reactor vesselof the IBR system.
 17. The method of claim 14 wherein the sparging gasis injected into the at least a portion of the substrate mixture that islocated within a pre-processing vessel of the IBR system.
 18. The methodof claim 14 wherein the nitrogen compound is ammonia.
 19. The method ofclaim 14 further comprising: detecting, via a sensor of the IBR system,a pH of the at least a portion of the substrate mixture or an amount orconcentration of a nitrogen compound in the substrate mixture; andcontrolling, by a controller of the IBR system, operation of thenitrogen reduction system based at least in part on the detected pH ofthe at least a portion of the substrate mixture or the amount orconcentration of the nitrogen compound in the substrate mixture.
 20. Themethod of claim 14 wherein the sparging gas comprises: ambient air; achemically inert gas; or steam.